The International Space Station. Credit: NASA

Sunday, June 10, 2012

NASA'S SPITZER FINDS FIRST OBJECTS BURNED FURIOUSLY


FROM:  NASA
WASHINGTON -- The faint, lumpy glow from the very first objects in the
universe may have been detected with the best precision yet using
NASA's Spitzer Space Telescope. The objects could be wildly massive
stars or voracious black holes. They are too far away to be seen
individually, but Spitzer has captured new, convincing evidence of
what appears to be the collective pattern of their infrared light.

The observations help confirm the first objects were numerous in
quantity and furiously burned cosmic fuel.

"These objects would have been tremendously bright," said Alexander
"Sasha" Kashlinsky of NASA's Goddard Space Flight Center in
Greenbelt, Md., lead author of a new paper appearing in The
Astrophysical Journal. "We can't yet directly rule out mysterious
sources for this light that could be coming from our nearby universe,
but it is now becoming increasingly likely that we are catching a
glimpse of an ancient epoch. Spitzer is laying down a roadmap for
NASA's upcoming James Webb Telescope, which will tell us exactly what
and where these first objects were."

Spitzer first caught hints of this remote pattern of light, known as
the cosmic infrared background, in 2005, and again with more
precision in 2007. Now, Spitzer is in the extended phase of its
mission, during which it performs more in-depth studies on specific
patches of the sky. Kashlinsky and his colleagues used Spitzer to
look at two patches of sky for more than 400 hours each.

The team then carefully subtracted all of the known stars and galaxies
in the images. Rather than being left with a black, empty patch of
sky, they found faint patterns of light with several telltale
characteristics of the cosmic infrared background. The lumps in the
pattern observed are consistent with the way the very distant objects
are thought to be clustered together.

Kashlinsky likens the observations to looking for Fourth of July
fireworks in New York City from Los Angeles. First, you would have to
remove all the foreground lights between the two cities, as well as
the blazing lights of New York City itself. You ultimately would be
left with a fuzzy map of how the fireworks are distributed, but they
would still be too distant to make out individually.

"We can gather clues from the light of the universe's first
fireworks," said Kashlinsky. "This is teaching us that the sources,
or the "sparks," are intensely burning their nuclear fuel."

The universe formed roughly 13.7 billion years ago in a fiery,
explosive Big Bang. With time, it cooled and, by around 500 million
years later, the first stars, galaxies and black holes began to take
shape. Astronomers say some of that "first light" may have traveled
billions of years to reach the Spitzer Space Telescope. The light
would have originated at visible or even ultraviolet wavelengths and
then, because of the expansion of the universe, stretched out to the
longer, infrared wavelengths observed by Spitzer.

The new study improves on previous observations by measuring this
cosmic infrared background out to scales equivalent to two full moons
-- significantly larger than what was detected before. Imagine trying
to find a pattern in the noise in an old-fashioned television set by
looking at just a small piece of the screen. It would be hard to know
for certain if a suspected pattern was real. By observing a larger
section of the screen, you would be able to resolve both small- and
large-scale patterns, further confirming your initial suspicion.

Likewise, astronomers using Spitzer have increased the amount of the
sky examined to obtain more definitive evidence of the cosmic
infrared background. The researchers plan to explore more patches of
sky in the future to gather more clues hidden in the light of this
ancient era.

"This is one of the reason's we are building the James Webb Space
Telescope," said Glenn Wahlgren, Spitzer program scientist at NASA
Headquarters in Washington. "Spitzer is giving us tantalizing clues,
but James Webb will tell us what really lies at the era where stars
first ignited."

Other authors are Richard Arendt of Goddard and the University of
Maryland in Baltimore; Matt Ashby and Giovanni Fazio of the
Harvard-Smithsonian Center for Astrophysics in Cambridge, Mass.; and
John Mather and Harvey Moseley of Goddard. Fazio led the initial
observations of these sky fields.

NASA's Jet Propulsion Laboratory (JPL), Pasadena, Calif., manages the
Spitzer Space Telescope mission for the agency's Science Mission
Directorate in Washington. Science operations are conducted at the
Spitzer Science Center at the California Institute of Technology
(Caltech) in Pasadena. Data are archived at the Infrared Science
Archive housed at the Infrared Processing and Analysis Center at
Caltech. Caltech manages JPL for NASA.

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